General Duct Insulation

Select insulation with a flame spread and smoke development index of 25/50 when tested in accordance with ASTM E84 or UL 723

Select insulation that includes an exterior vapor retarder layer

Remove damaged or wet duct insulation from premises

Verify ductwork is sealed before insulating

Insulate all ducts outside the thermal boundary to a minimum of R-8

Insulate all ducts exposed to the exterior to a minimum of R-12

Secure blanket insulation in full contact with the duct surface using mechanical fasteners (e.g., stick pins, metal wire)

Secure reflective insulation to duct in compliance with manufacturer specifications including required air spaces

Seal all seams and connections of the duct insulation using UL 181 approved tape so that no gaps exist in the vapor retarder

Post a dated receipt signed by the installer that minimally includes: Installed insulation type, coverage area, installed thickness, and installed R-value

If reflective exterior insulation is used the documentation must include the number and width of included air spaces